HVAC - EPA Certification Practice Exam

What is the characteristic of "temperature glide" in refrigerant blends?

1. It indicates a refrigerant cannot condense

2. It signifies a uniform boiling point

3. It reflects changing condensation temperatures

4. It denotes the time taken for evaporation

The correct answer is: It reflects changing condensation temperatures

Temperature glide in refrigerant blends refers to the phenomenon where the refrigerant does not have a single boiling point, but rather a range of temperatures at which it will change from a liquid to a gas. This characteristic occurs because refrigerant blends, which are mixtures of two or more refrigerants, can exhibit varying boiling points due to the different properties of each component in the blend. As the mixture changes state, the temperature at which the refrigerant condenses into a liquid will not be constant, leading to a gradual change in temperature—this is known as temperature glide. For example, as a refrigerant blend absorbs heat, the temperature may gradually increase as it transitions from liquid to vapor instead of maintaining a constant temperature throughout the phase change. This characteristic is particularly important in design and operation of HVAC systems, as it impacts efficiency and performance. Understanding temperature glide allows for better management of system performance and can lead to more accurate charging and operation of refrigeration and air conditioning systems.